Zimgxp
New member
The O2 sensor is reading lean, Almost seems like a vacuum leak. Video won't play again for me. How is the idle speed?
2003 Sunfire 2.2L Ecotec Rough Idle at Stoplight
- Thread starter bsr2002
- Start date
jmarty320
New member
These cars come with ACDelco Professional Iridium Spark Plug from the factory. If you are using a platinum tipped spark plug which is a good plug, chances are that your Sunfire will not react kindly to these. They need to have Iridium. If I had to guess, you didn't install Iridium and that's a good possibility as to why it's running rough.
bsr2002
New member
Turned out to be the timing chain. Never heard any rattling and no warning and one of the guides broke.
8 bent valves but that was all the damage we could see. Pistons looked okay and the cylinder head should be coming back from the shop today..
EaOutlaw
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Thanks for getting back to us, what do the tops of the pistons look like? are there any dents or chunks of carbon that came off when the valves hit the pistons?
If it was my car I would clean each piston carefully, without sanding or grinding away any material same with the block.
look for any dents in the pistons, then get a calibrated Industrial machinist straightedge and check each piston at top dead center with a feeler gauge set.
Write each measurement down for each cylinder the measurements should be exact. if the timing chain jumped a tooth or two causing this, and you drove the car like this, I would be concerned real concerned about bent rods.
If the chain let loose while cranking I wouldn't be so concerned, if the measurements are different cylinder to cylinder do not risk wasting your money.
Pull the rest of the engine and send the short block to a machine shop and have them inspect it.
Let the professionals whom inspected each rod and piston tell you it is all good or needs repair. again this is what I would do, the car is yours and your decision to make.
http://www.summitracing.com/parts/cbi-56429/overview/
If it was my car I would clean each piston carefully, without sanding or grinding away any material same with the block.
look for any dents in the pistons, then get a calibrated Industrial machinist straightedge and check each piston at top dead center with a feeler gauge set.
Write each measurement down for each cylinder the measurements should be exact. if the timing chain jumped a tooth or two causing this, and you drove the car like this, I would be concerned real concerned about bent rods.
If the chain let loose while cranking I wouldn't be so concerned, if the measurements are different cylinder to cylinder do not risk wasting your money.
Pull the rest of the engine and send the short block to a machine shop and have them inspect it.
Let the professionals whom inspected each rod and piston tell you it is all good or needs repair. again this is what I would do, the car is yours and your decision to make.
http://www.summitracing.com/parts/cbi-56429/overview/
______________________________
bsr2002
New member
Got lucky, pistons were fine. Everything happened on the cylinder head. Drove it last night! A side from the battery being a little weak drove great and no more rough idle... 